Classic Plans We purchased a cheap piece of plywood to draw the outline of the firewall that we think we will build. It is mostly round with less round top and bottom and left and right sides. (Final shape to be decided) Picture 2 is what we will need for the engine cowling. (the ring). We don't want to weld it to the engine mount, so we will make a series of steel brackets (we saw these on the steerrman) bolted on the engine mount, with welded steel attachments to the ring to hold it in place. Hard to explain, but maybe I'll be able to get some pictures when we make them.